1200221100 has 216 divisors, whose sum is σ = 4082099840. Its totient is φ = 294952320.

The previous prime is 1200221081. The next prime is 1200221107. The reversal of 1200221100 is 11220021.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (1200221107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1976997 + ... + 1977603.

Almost surely, 2^1200221100 is an apocalyptic number.

1200221100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1200221100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2041049920).

1200221100 is an abundant number, since it is smaller than the sum of its proper divisors (2881878740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1200221100 is a wasteful number, since it uses less digits than its factorization.

1200221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 666 (or 630 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1200221100 is about 34644.2073080046. The cubic root of 1200221100 is about 1062.7238301218.

Adding to 1200221100 its reverse (11220021), we get a palindrome (1211441121).

The spelling of 1200221100 in words is "one billion, two hundred million, two hundred twenty-one thousand, one hundred".